It was September 4, and London was becoming a Ghost Town. This date was when John Snow finally found a clue that linked to the rising epidemic of cholera, the wells, as he was searching for unpolluted drinking water. It was unsurprising that this clue linked to Snow’s debunking of the miasma theory.

The miasma theory, which was referenced in the previous chapters, sounded ridiculous to me, especially in its claim that “all smell is disease”. With a developed sense of medical knowledge, I knew that smell could not simply lead to such a high death rate. However, the miasma theory was a tradition that otherwise insightful medical and political scholars followed. Edwin Chadwick, who believed in using big government to protect the health and well being of citizens, Florence Nightingale, who challenged gender roles in the medical field, and Dickens, who criticized the abject conditions in which the poor dwellers of London had to live in, were all liberal thinkers. But even as liberal thinkers, they too fell victim to the belief in the miasma theory just like the conservative thinkers who believed that the poor people caused the illness on themselves. This made me think. Could liberals and conservatives alike misinterpret the causes of modern epidemics?

As he battled against the miasma theory, Snow found out the true reason of the high death rate: the well was poisoned. Snow already knew that the miasma theory was not the cause of a high death rate due to the Sewer-Hunter principle, that if all smell was disease, he would have been dead in seconds. Whitehead, in addition to Snow, was also rather critical of the miasma theory. Snow’s convincing case against the pump was that most of those who lived near the pump and drank from it regularly died. Snow’s round of questioning diminished the spread of cholera. What I learned from reading Chapters 4-6 is that in order to stop social problems and epidemics, one must break free from tradition.